Method and apparatus for folding endless flat tubes



Oct. 25, 1966 AHLBRANDT 3,280,704

METHOD AND APPARATUS FOR FOLDING ENDLESS FLAT TUBES Original Filed May6, 1963 4 Sheets$heet l Oct. 25, 1966 A. AHLBRANDT METHOD AND APPARATUSFOR FOLDING ENDLESS FLAT TUBES 4 Sheets-Sheet 2 Original Filed May 6,1963 I11 verzzor A. A Z Z @2772; fi e'/bz ji Oct. 25, 1966 A. AHLBRANDT3,280,704

METHOD AND APPARATUS FOR FOLDING ENDLESS FLAT TUBES 4 Sheets-Sheet 5Original Filed May 6, 1963 r 6 B M ,b m Fm I Q .9 v y w F H WU.# Z A. A

Oct. 25, 1966 A. AHLBRANDT 3,280,704

METHOD AND APPARATUS FOR FOLDING ENDLESS FLAT TUBES Original Filed May6, 1963 4 Sheets-Sheet 4 Fig. 77 //3 I75 five-175w A. A1 ZZH-z-ncZZUnited States Patent Ofiice 3,280,704 Patented Oct. 25, 1966 3,280,704METHQD AND APPARATUS FOR FOLDING ENDLESS FLAT TUBES Andreas Ahlbrandt,Uhlandstrasse 17, Lauterbach (Hessia), Germany Continuation ofapplication Ser. No. 278,092, May 6, 1963. This application Dec. 13,1965, Ser. No. 513,514 18 Claims. (Cl. 93-20) The present application isa continuation of application Serial No. 278,092, filed May 6, 1963, nowabandoned and is a copending application to an application Serial No.234,285, filed December 10, 1962, now Patent No. 3,185,044. The presentinvention relates to a device for folding endless flat tubes. In theabove-mentioned copending application there is described a method offolding the lateral marginal portions of endless fiat tubes intended foruse in the manufacture of bags or sacks which, in a filled condition,will approximately assume the shape of a parallelepiped. According tothe copending application, the tube, during its continuous longitudinalmotion, is turned about its longitudinal axis by one half of the widthof one of its lateral surfaces; in other words, any point lying on theflat tubular web is offset in a lateral direction by one-half of thewidth of one lateral surface thereof in a direction perpendicular to thelongitudinal line. This method affords a solution to the problem ofproviding the bags or sacks with a continuous print impression whichwill not be interrupted by a lateral-edge folding line, since theportions intended to form the lateral surfaces, before being turned, liecompletely in the upper and lower parts respectively of the web. In theconventional practice, the areas intended to form the lateral surfaceslie partly (one-half) in the upper portion of the tubular web, andpartly (one-half) in the lower portion of the tubular web while theprinted impression is being applied.

An object of the present invention is to provide a method formanufacturing bags or sacks having no lateral folds, especially thewell-known cross bottom or satchel bags, by turning an endless fiat tubehaving printing impressions on its lateral marginal surfaces by one-halfof the width of said lateral surfaces, in order to achieve bags or sackshaving a continuous printed impression which will not be interrupted bya lateral folding line.

The present invention further relates to a device adapted to carry intoeffect the method of the invention in the manufacture of bags or sackshaving no lateral folds.

Other objects and features of the invention will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawings illustrating several preferred embodiments of theinvention wherein:

FIG. 1 is a plan view of a folding device according to the invention;

FIG. 2 is a longitudinal cross-sectional view of the folding device ofFIG. 1 taken along line II-II;

FIG. 3 is a longitudinal cross-sectional view resembling FIG. 2 butshowing a modified embodiment of the invention;

FIGS. 4 to 8, respectively, show cross-sectional views taken along thelines IV-IV to VIIIVIII in FIG. 1;

FIG. 9 is a plan view of another embodiment of a device for carryinginto practice the method of the invention;

FIG. 10 is a side elevational view of the embodiment of FIG. 9;

FIG. 11 is a cross-sectional view of the embodiment of FIG. 9 takenalong the line XI-XI;

FIGS. 12 to 16 diagrammatically illustrate the various steps performedby the device of FIGS. 9 to 11;

FIG. 17 is a side elevational view of still another embodiment of theinvention; and

FIG. 18 is a plan view of the embodiment of FIG. 17.

Referring to the drawings, the folding device shown in FIGS. 1 and 2comprises two identically constructed guide plates and 101 disposed andfastened to either side of a supporting member 108. The two guidingplates carry rotatable discs 102 on their diagonally opposed corners inorder to reduce friction. As shown in FIG. 2, the guiding plates 100 and101, the supporting member 108, and the discs 102 are disposed within anendless flat tube which is to be turned and folded. Their weight isborne by rollers 106 which are rotatably mounted in the frame of thedevice. The rollers 106 cooperate with rollers 107 which areinterconnected by axles and are carried for rotation on the supportingmemer 108, i.e. the lower half of tube 130 runs between rollers 106 and107. The rollers 106 and 107 are disposed with their axes extending atan angle to the longitudinal center line of the device and perpendicularto the guiding edges of the guiding plate 101. This arrangement isnecessary because the lower wall of the tubular web which is guided bythe guiding plate 101 is moving at an angle to its original direction oftravel.

The frame of the device is formed by channel sections 131. Pairs ofspindles 132 and rollers 133, between which the tube is pulled through,are mounted in the channel sections 131. Rollers 134, which are securedto the front and back ends of the supporting members 108, bear againstthe rollers 133. The rollers 134 receive the thrust exerted by the tube130 on the guide plates 100 and 101. At the off-running end of thedevice, spindles 135 are secured to the frame uprights 137. The spindles135 carry a pair of rollers 136 which act to press together the foldedtube 130. Longitudinal frame members 138, extending parallel to thecentral axis of the folding device, are secured to the channel sections131. Displaceab-ly mounted thereon are bearers 139 and 140 disposed inpairs and within the latter are movably mounted displaceable rods 14-1on the ends of which are mounted either guide rollers 142 or foldingdiscs 104. The rollers 142 are provided in greater numbers than shown inthe drawings. Only a limited number have been shown for the sake ofclarity.

As will be seen by FIGS. 1 and 2, the two guiding plates 100 and101,'which carry the rotatable discs 102 on diagonally opposed corners,are disposed in two parallel planes and cross in space. The amount ofrelative displacement of the plates is the same on the ion-coming sideand on the off-running side of the guiding plate. The printedimpressions 103, which are indicated in dotted lines in FIGS. 4 to 8,show the width of the lateral surfaces formed subsequently as parts ofthe bags or sacks .to be manufactured. It will be seen in FIGS. 1 and 5that the distance between the guiding edges of the plates 100 and 101 onboth sides of the tube on the on-coming side of the device amounts toapproximately one-half only of the width of the lateral surface. Sincethe guiding edges of the plates 100 and 101 cross in space at the centerof the device, the tubular web would no longer be held taut at thispoint unless it were folded inwardly, as shown in FIG. 6, by therotatable disc 104 extending from the outside into the gap between theplates 100 and 101. The discs 104 serve to produce inwardly extendingfolds 105 which are, however, exclusively intended to tension thetubular web, the folds being folded outwardly again at a later stage ofmanufacture As shown in FIG. 6 one-half of the printed impressions onthe lateral surfaces are disposed on the upper side of the tubular webin the region of the discs 104, the other half being disposed on theunderside of the web. The inner half of the lateral surface is foldedinto the space between the plates 100 and 101 by the respective discs104. As the motion of the tubular web continues, the right-hand portionthereof is again spread outwardly by the guiding edge of the plate 101,the left-hand portion of the web being similarly spread outwardly by theguiding edge of plate 100, it being understood that, due to the distancebetween the guiding plates transversely to the central plane of thetubular web, the guiding edge engaging the web towards the off-runningend of the device will produce its spreading action at the center lineof the printed impressions applied on the lateral surfaces. In thismanner there is produced a flattened tube, shown in FIG. 8, in which thetwo halves of the printed impressions are respectively disposed on theupper and lower sides of the web.

It is possible to eliminate the discs 104 and thus to omit the step oftemporarily producing the lateral folded-in portions by providingguiding plates having a longitudinal across section of the shape shownin FIG. 3. In this case, the guiding plates are divergent up to thecrossing point and thereafter converge again, the distance between theplate on the off-running side being again the same as that on theon-coming side. The increased distance between the plates, intermediatetheir ends, insures that the tubular web will be held taut- Anotherembodiment of the invention is shown in FIGS. 9-11. The framework ofthis embodiment comprises longitudinal frame member 145 to which arefastened frame uprights 144. At the on-coming end of the device, thetube 130 is guided by a roller 143 which is rotatably mounted between apair of the frame uprights 144. A pair of rollers 146 and 147 follow theroller 143 in the running direction of the tube 130. The roller 146 .isrotatably mounted on a spindle 1149 while the roller 147 is rotatablymounted in arms 148 which are secured to the spindle 149. The spindle149 is secured between a pair of uprights 144 and at one endis providedwith a screw 109 having a hand crank 110 and extending through one ofthe longitudinal frame members 145. The screwserves to vary the angle ofinclination of the rollers 146 and 147 with respect to the central planeof the folding device. The oblique disposition of the rollers. 146 and147 is apparent from FIG. 11 which also shows themobility of the spindle149 relative to the frame of the device.

A supporting member 150 is located in the middle axis of the tube andcarries at one end an arm 151 on which two discs 152 and 153 arerotatably mounted. The arm 151 can swivel relative to the supportingmember 150 and is set at the same angle as the pair of rollers 146 and147. The spacing between the outer discs edges approximately correspondsto the tube width, as shown in FIG. 13. Forks 154, each carrying aroller 155, are secured through the supporting member 150 approximatelymidway between the rollers 152 and 153 and rollers 111, shown at rig-htangles to the supporting member. The rollers 111 are rotatably mountedon a spindle 163 Which is secured to a pair of uprights 144. The otherend of the supporting member is provided with rollers 156 which bear ona pair of rollers 157 which is turn are rotatably mounted on a spindle158 secured to a pair of uprights 144. The rollers 156 serve to receivethe thrust exerted by the tube on the supporting members 150. The lowerroller 155 bears on a roller 159 which is rotatably mounted on a spindle160 secured in a pair of frame uprights 144 (FIG. 11). A spreadingdevice 161, made of thin wire or guiding plates, is secured near the arm151 on the supporting member 150. A similar spreading device 162 issecured between the rollers 155 and the rollers 111. The tubular web,after having been spread in the spreading devices 161 and 162',isreflattened by the rollers 111 and spread by means of the spreadingdiscs 112. Thus, the tubular web will emerge from the device again inthe form of a flattened tube, but it will have turned in acircumferential direction by one-half of the width of a lateral surfacethereof. At the off-running end of the device, again a pair of rollers164, rotatably mounted on spindle 165 4 secured to a pair of uprights144, act to press together the folded tube 130.

The sequence of steps performed by the second embodiment of theinvention will now be described with reference to FIGS. 12 to 16. Theendless flat tube, shown in FIG. 12, is preferably made of athermoplastic material and is intended, for example, for the manufactureof bags or sacks. It has two lateral edges a and d. The flat tube isprovided with printed impressions which will subsequently app-ear on thelateral surfaces, which are indicated in FIG. 12 between the lines a andc and the lines d and 1, respectively. It will be seen in FIG. 12 thatthe printed impressions, which will appear on the lateral surfaces, may

be applied simultaneously with those which are to appear.

on the wider surfaces of the bags or sacks. In FIGS. 13 to 15, dottedlines indicate those portions of the tube material which are intendedsubsequently to form the lateral surfaces. FIG. 13 shows the middleplane of the tube turned through an angle of a. The position of thelines a-f relative to the axis of the tube has remained unchanged. Theturning of the plane of the tube is caused by the oblique position ofthe two rollers 146 and 147 and the rollers 152 and 153.- Theinclination of these rollers relative to the middle plane of the foldingdevice is so adjusted that the tube-is turned through half the width ofthe lateral surface thereof. As is shown in FIG. 14 the tube is thendrawn out of the oblique position into a plane forming an angle degreesor approximately 90 degrees,

with the middle plane of the folding device. This operation is carriedout by means of the pair of rollers 155 which, simultaneously with thedisplacement of the plane of the tube, cause a turning of the tube aboutits middle axisthrough half the width'of a lateral surface to be formedthereof. Following this step, the tube is flattened again by the rollers111 and spread by the spreading discs 112, as illustrated in FIG. 15. Inthis condition, there have been formed the new lateral edges b and ewhich are centered between lines a and c and the lines d and 1,respectively. FIG. 16 shows the tube which has been rotated by one-halfthe width of one lateral surface about its longitudinal axis.- Thetubeleaving the device of FIGS. 9 to 11 is in this form.

FIGS. 17 and 18 show a modification of the embodiment of FIGS. 9 to 11in which the function of the tiltable guide rolls on the entry end ofthe device has been replaced by providing for the axle 113 of the supplyreel. 114

to be tilted as required. Two later-a1 spaced apart cheeks 115,connected by a rear wall 117 support the supply reel 114 and a guideroll 11-6. The upper edge of rear wall 117 is inclined upwardly from theupper edges of the cheeks forming surfaces 118 and 119. The rear wall117 is supported for rotation about a pin 120 mounted in a frame 121; Aworm wheel 122 is fixedly secured to the rear wall 117 and is disposedon the axis of the pin 120.

A worm gear 123 cooperates with the worm wheel122'.

with the aid of a spindle 124 journaled in arms 125 of the bracket 121to tilt the rear wall 120, the cheeks 115 and the rolls 114 and 116. Thetil-ting is actuated by turning hand crank 126. The inclination of thesurfaces 118 and 119 of the upper edge of rear Wall 117 is necessary topermit the worm wheel 122 to be mounted at a suificiently high. level sothat the upper edges of the cheeks 115, when being swung round, will notfoul against the spindle 124.,

The spreading device shown in the left-hand portions: of FIGS. 17 and 18corresponds to the previously described spreading device of FIGS. 9and-ll. Therefore, the description of this device will not be repeated.However, there is indicated at 127 a triangular spreading plate whosefunction it is to initiate the spreading apart of the two walls of thetube preparatory to the final spreading.

action. This action is complemented by the action of the spreading discsmounted downstream of the plate 127.

What is claimed is: 1. A method of transforming a continuously movingflattened tube of artificial material which tube is characterized by twodiametrically opposed fold lines and indicia along at least one marginalouter surface region lying adjacent to and on one side of one of thefold lines comprising the steps of spreading the tube to open same,keeping said tube taut, rotating said tube about its longitudinal axis adistance equivalent to one half the Width of the marginal outer surfaceregion, and thereafter refiattening the open tube along newdiametrically opposed fold lines parallel to but displaced from theoriginal fold lines, one of said new fold lines lying midway of themarginal outer surface region so that the indicia now lie in marginalsurface areas adjacent to but on opposite sides of said one new foldline.

2. A method according to claim 1 in which said tube is kept taut bytemporarily forming inwardly directed accordian pleats in opposite sidesof the tube adjacent to the new fold lines during its transformation.

3. A method according to claim 1 in which said tube is kept taut byvertically expanding a central portion of said tube during itstransformation.

4. An apparatus for folding continuously moving fiat tube-like webshaving two diametrically opposed fold lines and at least onelongitudinally extending marginal portion bearing indicia along one ofthe fold lines and intended to be used to produce package bagscomprising means for continuously moving the web longitudinally, meansfor spreading the web from within to open same, means for rotating thweb about its longitudinal axis a distance which is equivalent to onehalf the width of the marginal portion of the Web to shift the indicia,means for keeping the periphery of said web taut during the rotation,and means for refolding the web along new diametrically opposed foldlines rotatably displaced from the original diametrically opposed foldlines with the indicia straddling one of the new fold lines.

5. An apparatus for transforming a flat running tubelike web havingindicia on a marginal portion thereof comprising internal structuralmeans including elongated first and second guide means oriented in thedirection of longitudinal travel of the web, means supporting said guidemeans spaced apart in a direction perpendicular to the intended plane oftravel of the web in spacial lateral displacement at both ends, said webbeing fed over said internal structure means and opened out thereby,means to support and retain the position of the internal structuralmeans when a web is fed over same, means adapted to act on the lateralportions of said web as it passes over the internal structural means toinitiate tautness in said web during the translation thereof, and meansadapted to refiatten the web along new fold lines.

6. An apparatus for folding a flat running tube-like web according toclaim 5 in which said means for inducing a tautness in the web comprisesmeans adapted to act on the external lateral portions of said web as itpasses over the internal structural means to initiate inwardly directedfolds in the middle of one half of the marginal portion having indiciaand the portion immediately diametrically opposed thereto, said inwardlydirected folds being removed prior to the final folding of said web.

7. An apparatus for folding a flat running tube-like web according toclaim 5 wherein the means to maintain tautness in said web comprisessaid guide means vertically diverging from the onrunning end andvertically converging towards the offrunning end, said guide means beingat their maximum spacial relationship substantially at the medianportion thereof.

8. A device for transforming an endless flattened tubular web ofartificial material intended for the manu facture of bags, sacks and thelike comprising spaced guiding means disposed within a moving tubularweb, said guiding means spreading open said web, guiding edges of saidguiding means engaging with the lateral edges of said web, said guidingmeans being disposed in opposing pairs on the outermost diagonal cornersof a pair of spaced surfaces whose longitudinal medial axes intersectone another :at an acute angle, said surfaces being spaced perpendicularto the central plane of the tubular web, the distance between saidguiding edges on the oncoming and olfrunning sides amounting toapproximately one half the width of the lateral surfaces of the bags,sacks and the like to be produced.

9. A device for transforming an endless flattened tubular web accordingto claim 8 wherein said surfaces are parallel planar surfaces and inwhich means are provided to form at least one inwardly directed fold insaid tubular web intermediate the ends of said parallel planar surfacesto insure a tautness of said web, said folds being removed prior to thefinal folding of said web.

It). A device according to claim 8 in which additional guiding means aredisposed in the :region of the lines of intersection of the surfacescontaining the guiding edges and extending parallel to the central planeof the tube, said additional guiding means extending from the outsidecentrally into the space between the first mentioned guiding means, theadditional guiding means extending into said space a distanceapproximately equaling one half the amount through which it is desiredto rotate the tubular web about its axis.

11. A device according to claim 9 in which said additional guiding meanscomprise a pair of rollers externally engaging the tube web and carriedby displaceable rods and said guiding means comprise pairs of discsadapted to spread the tubular web from within.

12. A device for folding continuously moving flat tube-like webs havingtwo diametrically opposed fold lines and at least one longitudinallyextending marginal portion bearing indicia along one of the fold linesand intended to be used to produce package bags comprising means forcontinuously moving the web longitudinally, means for spreading the webfrom within, said spreading means comprising means for engaging theinner surface of said web along diametrically opposed lines lying in aplane oblique to the onrunnin'g plane of said web, said means forengaging the inner surface of said Web being disposed between two spacedguiding means, the planes of said guiding means subtending an anglecorresponding to the amount through which the tubular web is to berotated about its axis, and means for refolding the web along newdiametrically opposed fold lines rotatably displaced from the originaldiametrically opposed fold lines with the indicia straddling one of thenew fold lines.

13. A device according to claim 12 wherein the said means for engagingthe inner surface of said webs consist of spreading discs.

14-. A device according to claim 12 in which the angle between saidguiding means is adjustable.

15. A device according to claim 12 wherein a reel holding a supply ofthe tubular web material is rotatably mounted on an axis inclined fromthe horizontal so as to serve as a guiding structure at the oncoming endof the device.

16. The device according to claim 12 wherein a spreading plate isdisposed within the tubular web upstream of said spreading discs.

17. A device according to claim 12 wherein the said spreading meansfurther comprises guiding plates.

18. A device according to claim 12 wherein the said spreading meansfurther comprise a guiding structure made of bent wire.

No references cited.

BERNARD STICKNEY, Primary Examiner.

5. AN APPARATUS FOR TRANSFORMING A FLAT RUNNING TUBELIKE WEB HAVINGINDICIA ON A MARGINAL PORTION THEREOF COMPRISING INTERNAL STRUCTURALMEANS INCLUDING ELONGATED FIRST AND SECOND GUIDE MEANS ORIENTED IN THEDIRECTION OF LONGITUDINAL TRAVEL OF THE WEB, MEANS SUPPORTING SAID GUIDEMEANS SPACED APART IN A DIRECTION PERPENDICULAR TO THE INTENDED PLANETRAVEL OF THE WEB IN SPACIAL LATERAL DISPLACEMENT AT BOTH ENDS, SAID WEBBEING FED OVER SAID INTERNAL STRUCTURE MEANS AND OPENED OUT THEREBY,MEANS TO SUPPORT AND RETAIN THE POSITION OF THE INTERNAL STRUCTURALMEANS WHEN A WEB IS FED OVER SAME, MEANS ADAPTED TO ACT ON THE LATERALPORTIONS OF SAID WEB AS IT PASSES OVER THE INTERNAL STRUCTURAL MEANS TOINITIATE TAUTNESS IN SAID WEB DURING THE TRANSLATION THEREOF, AND MEANSADAPTED TO REFLATTEN THE WEB ALONG NEW FOLD LINES.